The invention relates to the field of electrical protection, and is particularly directed to a fusible link for protecting electrical devices.
Automobiles are increasingly reliant on electronic controls and engine management systems. As a result of these controls and systems, modern automobiles are much more dependable than prior autos, which instead used more vulnerable mechanical systems. Although the hardware embodying the electronic controls and systems is rather dependable, the failure of the means for directly or indirectly bringing electrical current to such hardware continues to be a rare but, nevertheless, significant source of automotive breakdowns. An automotive breakdown, especially in a deserted area or on a very busy high-speed road, is obviously a safety hazard to the automobile and its passengers.
One specific type of failure in prior art means can lead to an even more hazardous condition than automotive breakdown. The failure results when the junctions between the fusible link and the cables loosen, causing a high resistance between the fusible link and cable. The increased resistance leads to high temperatures in these regions. One cause of the failure at the connection of the fusible link and the cable is due to the flexibility of the fusible link. If the fusible link is not sufficiently rigid it may twist and bend during use of the cable assembly, thereby causing the connection between the fusible link and the cable to fail. Under certain conditions the increased temperatures can reach sufficiently high levels to split the insulation on the conventional copper-wire fusible links, initiating an engine compartment fire that can quickly destroy the automobile and endanger its occupants.
U.S. Pat. No. 5,591,366 issued to Schmidt et al. discloses a series of protective coverings over a heating wire connected to a power wire. The heating wire is connected in series to an electrical pin which directly joined to a fuse wire. The fuse wire is then joined to the power wire. Two opposing metal caps are bonded on their inner surfaces to a ceramic tube to form a hermetically sealed shell surrounding the junctions between the fuse wire and pin, and between the fuse wire and power wire. Then, a heat shrinkable tubing is used to grip the caps and ceramic tubing, encasing the fuse area.
Like other prior art devices, the disclosure of U.S. Pat. No. 5,591,366 does not solve the problem of protecting failure at the junctions of the fusible link.
Accordingly, a fusible link for a cable assembly in accordance with the present invention eliminates the drawbacks of the prior art devices described above.
According to one aspect of the present invention, a fusible link is provided for a cable assembly. The fusible link has a link segment having a first member extending transversely from the link segment, and a second member extending transversely from the link segment. The link segment is adapted to be electrically connected to first and second cables of the cable assembly.
According to another aspect of the present invention, the link segment has a first end and a second end, a first surface and a second surface, and a first side and a second side. The first end of the link segment is adapted to engage the first cable of the cable assembly and the second end of the link segment is adapted to engage the second cable of the cable assembly to electrically connect the fusible link with the first and second cables. The first member extends from the first side of the link segment and the second member extends from the second side of the link segment. The first and second members are transverse to the link segment.
According to another aspect of the present invention, the first member extends in a first direction transverse from the link segment, and the second member extends in a second direction from the link segment. In one embodiment, the second direction is substantially the same direction as the first direction. In another embodiment the second direction is substantially the opposite as the first direction.
According to another aspect of the present invention, the link segment is substantially planar and a plurality of apertures extend through the link segment. The fusible link may be made of a first conductive material that is the same as the conductive material as the first and second cables, and a second conductive material having a lower melting temperature than the first conductive material may be deposited on the link segment.
According to another aspect of the present invention, a method of manufacturing the fusible link is provided. The method includes providing a strip of conductive material having a first surface and a second surface. An aperture is created in the conductive material. The aperture extends from the first surface of the conductive material to the second surface of the conductive material. Additionally, transverse members are created on the fusible link.
According to another aspect of the present invention, the step of creating the transverse members comprises bending a first side of the strip of conductive material at an angle to the first surface to create a first transverse member, and bending the second side of the conductive material at an angle to the first surface to create a second transverse member.
According to another aspect of the present invention, a method of manufacturing a plurality of fusible links is provided. The method includes dicing the strip of conductive material into individual fusible links prior to creating the transverse members.
According to yet another aspect of the present invention, an additional step is provided including adding a second conductive material having a lower melting temperature than the first conductive material on one of the first and second surfaces of the fusible link. The second conductive material is added adjacent the aperture in the conductive material.
Other features and advantages of the invention will be apparent from the following specification taken in conjunction with the following drawings.